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Raman Spectra of Isotopic‐Disordered Group IV Semiconductors: A First Principles Approach
Author(s) -
Steininger B.,
Pavone P.,
Strauch D.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199909)215:1<127::aid-pssb127>3.0.co;2-s
Subject(s) - coherent potential approximation , supercell , raman spectroscopy , diamond , lattice (music) , phonon , semiconductor , spectral line , raman scattering , condensed matter physics , materials science , molecular physics , physics , atomic physics , electronic structure , quantum mechanics , thunderstorm , meteorology , acoustics , composite material
Abstract We present theoretical results of the off‐resonance Raman spectra, phonon density of states and self‐energies of isotopic‐disordered diamond, Si, Ge, and α‐Sn. Modern first‐principles techniques are used to obtain the lattice‐dynamical properties which are the base of our calculations. We simulated isotopic‐disordered systems using supercells containing up to 512 atoms per unit cell and compared our results with the virtual‐crystal approximation (VCA) and the coherent‐potential approximation (CPA). We show the equivalence of CPA and supercell methods when using as input the same lattice‐dynamical quantities, whereas the VCA fails to obtain the correct trends. We proved that supercells of the size of a few hundred atoms are sufficient to describe the main disorder‐induced features in good agreement with experimental results.